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Digital Dan,
Thanks for the reach out! Yeah, did the same thing and am now able to get 8900 out of the machine per the gauge on the dash. Definitely better, but like you say, you still bang up against the cutout at 8900 rpm, which is still only about giving me 36 mph on the speedo. Much better than where we were, but still will be annoying on the roads, especially heading downhill. It now seems that we are not loading the engine enough to keep it from banging up against the max rev limiter. The obvious next step is to change the final gearing from 42 tooth final sprocket to a 40 tooth. I am also planning on getting a 38 tooth as well. The final gearing ration change should give us taller gearing and make it more tough for the engine to pull so strong to 8900 rpm. Unless you beat me to it, i"ll let you know what I find with the gearing changes we are both making the exact same mods. BTW - Matt at 250UTV.com (aka Strike 250 Advanced Member on this blog) has been incredibly helpful for me on this journey! He is a Strike 250 Rock Star!!! For those of you that are really trying to get their Strike 250 to shine, please visit his website at www.250UTV.com, he has got some real goodies for this machine..

Awesome, for sure I will mention you!! Also, can you explain what the Speed limiter 37910-120-0000 under the dash does? I believe this is what you referred to in past comments? What does it do and why would they have both a separate limiter and the rev limiter in the engine?

Awesome info!!! So assuming we can get the ECU rpm limit changed, via reprogramming or a getting an 2015 unit, then all we have to do is compensate for the gearing changes. So it's unlikely that those of us with slow units will make the internal engine changes, but we should be able to compensate for the reduction on the final sprockets, right? Are you confident that just changing the rear sprocket to 38 will help, or will we have to go much lower in tooth count? Also, what does a stock 2015 unit max out on in respect to revs?

When you say "gearing inside the engine" what does that mean? In the 2 speed geared transmission, in the CVT, or the final sprocket ratio? This is great information, please share more insight if possible. Thanks!!

Hey thanks again everyone for helping me with my original question.. Bear with me, but I am still confused as to how all of us that bought 2017 or newer units can get back to the prior models performance where the top speed was much faster. (up to 50 mph per magazines reviews) .
If any Advanced Members can make it really clear what Hisun exactly did to slow the machine down, then the the rest of us with 2017 machines have a chance at getting the top speed back.
I have been told that the EFI module (Delphi MT05) has been reprogrammed and a spark cutoff has been added at 7000 rpm. I can confirm the cutoff with my machine! It makes it extremely annoying for anyone to ride behind this machine on the trails and roads while the engine continuously hits up against the cutoff. It does not just happen once and a while, but all the time while riding! It's terrible! Sounds like the machine is constantly backfiring! If this is really true, then we should be able to replace the current 2017 ECU with an older pre 2017 version with the old software, right? If anyone can answer this question, that would be really good to know. Not a cheap solution, but at least gets us back to where we expected the machine to perform and eliminates the extremely annoying lower spark cutout at 7000 rpm... Also, for anyone that has a pre 2017 machine, can you confirm what is the max RPM you get off the dash when you have the machine at full throttle? Is it 7500, 8000, 8500 or what? This will help us understand what else was changed on the machine to effect the top speed.
I have also been told by people in the blog that the final ratio on the machine has been changed as well on the 2017. I currently have 11 tooth drive gear and 42 teeth on the final sprocket. It has been suggested to change the final sprocket to 38 to get some speed back. Unfortunately when I do the math, you only gain 3.1 mph. This helps a bit, but I am still way off in my mission to go from 30 mph to 50 mph... So I am still confused. See the math and the speed table I have attached. I am not very smart, so if anyone can show me the error in my calcs, feel free to correct. Note: Since I was not able to count the gear teeth in the gear transmission, I solved backwards for the gear transmission ratio in high gear to be 4:1. At engine an speed of 7000 rpm, 4:1 ratio in the transmission, 11/42 ratio on the final sprockets, and a 22 in dia. tire, it gives me my current measured speed off the machine (gps) of 30mph. Just to be sure, if anyone can confirm the transmission ratio to be 4:1 in high, that would help as well as what is the tooth count for the Drive and Driven sprockets on machines pre 2017. This would also be huge because then in addition to changing out the ECU, we could simply just buy the older sprockets (and chain) with the original ratio and get our speed back!
Now, I still have one more area that we did not address.. The CVT. Did they change it to effect the top speed? On my little 90 cc Kawasaki ATV, they put a spacer in the primary clutch to prevent it from closing all the way and get the final ratio. I heard this was common on the smaller kids machines to slow them down when the kids were small, and could be removed by parents as the kids got older. Can anyone comment as to whether Hisun would have modified the primary clutch on the 2017 models, limiting the travel of the two sheaves? I still think about this one because when I ride the machine, it seem to climb to 7000 rpm very quickly and then cutout. It definitely feels there should be more top speed prior to hitting the cutoff. It feels as thought the clutches cannot get to their final ratio. (belt highest on Drive clutch, lowest on Driven clutch) Any insights?
The last question I have is related to the response I got from Strike 250 Advanced Member:
Hello there, there are a couple of things to address here. First off is to make sure when the throttle peddle pressed all the way down, that the throttle is also opening all the way. You can check this by removing the center cover. When you press down on the throttle, reach over to the butterfly valve and see if you can open the throttle any more on the throttle body. If so, adjust the throttle cable. But you need to make sure when the throttle is released that the throttle also closes as well. Meaning you will have just a little bit of slack in the throttle cable. You don't want the throttle body hanging up causing the engine to rev. After that, there is come control in the ECU, but there is also a electronic speed limiter, located under the dash by the winch control box. Try to make sure the throttle is adjusted properly first and let me know. Matt
I have not got a chance to adjust the throttle cable yet, but I will follow your advice. Since I was accelerating good up to 7000 rpm and the cutout was kicking in, it did not seem like my issue was a partial throttle condition, but I will chack any how. The big questions I have is the "electronic speed limiter under the dash" that you mentioned... What exactly is this and what does it look like? Is this the real problem? Nobody else could confirm this existed.. Could not find it the first time I looked. Any more information you can give on this would be AWESOME!!
BTW, my dealer has been totally useless since I gave him the check, so it anyone can recommend a good place to get parts for the unit, let me know. Thanks!
Please, if anyone can help out and make this speed thing simple, it would be great for the rest of us! Even better would be if someone was to offer a kit will all the components to get the machine to perform at pre 2017, I bet everyone would buy it!!
Love the machine, hate the performance!
Fun Dad
Strike 250 Speed Calculations.xlsx

My first impression are that the quality is good, not great. I have had the machine up on two ATV trips to Northern Wisconsin and honestly had to go over the machine to get things right. The squeaks and rattles drove me nuts and required me to tear parts of the machine apart to figure them out. If you are not very handy, go with the Polaris unit.
I ended up not leaving the machine at camp and decide to bring it back home to do more work on it to get everything right. My dealer is no help, so I have to do the work myself.
If you do get one, these forums will help you get the machine right.

The HiSun Strike 250 is really a kids machine, not ideal for an adult. I just bought a 2017 for the kids and I am 5'11" and weigh 175 and I barely fit into the machine. The new machines are also speed limited to 30mph, so it could get rather boring quickly. I would not recommend it.
Polaris RZR 570 would be my recommendation, a bit wider, but great entry level UTV for adults.

Guys,
I need some expert help.. I just bought a 2017 HiSUN Strike 250 and was real disappointed to find out that there is an electronic spark cut out at 30 mph. Every article that I read prior to purchase said that the unit could hit 45-50 mph with the pedal stop screw removed. Not the case with my machine. Never bothered to ask the dealer before purchase, so it is my fault... My guess is that HiSun got some flack about thier "kids" machine doing 50 mph and were forced to add the electronic limiter.. Can anyone verify that previous to the 2017 model that the machine can actually could do 45-50mph with the just pedal screw removed? If so, what RPM is it at when doing 45-50 mph. Maybe I can get an older version of the Delphi ECU, assuming that is where the spark cut out is located...?
The machine is definitly full featured, but as you all mention, needs to be gone over after purchase. A-men to stipped screws, and if you suffer from a crazy squeak sound that sounds like chains dragging, check the torque on the suspension a-arms and shocks. Ours were so tight, we could barley get them loose and the suspension would not move, essentially zero travel. Once we lightened up the torque, greased the plastic bushings, and added blue threadlocker, the suspension actually worked and all the squeaks went away. Also have same problem with the shift linkage rubbing on pipe and also pipe rubbing on chassis.. This weeks project!
Any help on the speed would be awesome!